Following the death of Gerald Kaufman, there will be a by-election in his constituency of Manchester Gorton. It is likely to be held on May 4 — the same day as local elections and the inaugural, George Osborne-inspired, Greater Manchester mayoral election.

In normal times the by-election would pass with little comment. The seat has been held by Labour since 1935 and Kaufman was elected in 2015 with 67 per cent of the vote, Labour’s 15th-highest share. His nearest rival, the Green candidate, received under ten per cent. The Labour candidate, Pakistani-born MEP Afzal Khan — every bit as much an Israel-hater as Kaufman — could have expected to have a job for life. The Boundary Commission’s initial proposals for the 2018 parliamentary constituency review, which seek to implement the government’s desire to reduce the size of the House of Commons from 650 to 600 and to make constituency sizes more equal, make no changes whatsoever to Manchester Gorton.

Jeremy Corbyn has, however, changed all that. Labour is now 20 percentage points behind the Tories in the polls, and even his erstwhile cheerleader, Guardian columnist George Monbiot, says of him on Twitter: “Corbyn has proved completely useless . . . JC could scarcely have made a bigger hash of it by design.” Moreover, the Labour Party in Manchester Gorton is in some disarray, with the constituency association having been in special measures since 2004 and the candidate shortlist for the by-election handled by a five-strong centrally appointed panel. This panel — to the apparent annoyance of Corbyn, who wanted his ally, the Salford MP Rebecca Long-Bailey, on it instead — included the Leicester MP Keith Vaz despite his recent discussions about washing-machines with Romanian rent boys.

Labour, of course, lost the Copeland by-election in February to the Conservatives, the first time a governing party has gained a seat in a by-election for 35 years or — if the 1982 Mitcham and Morden by-election is discounted, as the sitting MP had defected to the SDP and was seeking his constituents’ sanction for the move — 57 years. Could the same happen in Manchester Gorton?

Copeland had also sent only Labour MPs to Westminster throughout its history but it had been a much less safe seat. Labour’s majority in Copeland was 6 per cent, as opposed to 57 per cent in Manchester Gorton, which is also much more ethnically mixed: 47 per cent of its population is non-white, with parts of the constituency having a large black population and others being heavily of Pakistani background. Both these groups have proved more loyal to Labour than white working-class voters.